The invention relates to an electric machine which includes a first magnetic pole having an arrangement of layers with magnetically active layers and a second magnetic pole moveable relative to the first magnetic pole and spaced from the first magnetic pole by a pap, and an electric conductor as a coupling element between an electric circuit and a magnetic circuit, wherein for electromechanical energy conversion the magnetic circuit includes the first magnetic pole, the pap and a second magnetic pole. The invention also relates to a magnetic pole part with the aforedescribed first magnetic pole with the arrangement of layers, a vehicle and a wind turbine as well as a method for producing an electric machine of this type.
Electric machines of the aforementioned type can be used as a drive motor or as a generator. One reason for the increased use of electric machines as a drive motor is that because of the scarcity of fossil fuels an alternative must be found to conventional internal combustion engines. Reliance is in this case being placed on renewable energy sources as a replacement for fossil fuels. Because a renewable energy source is not always available at the right time and place, the renewable energy has to be converted into a form of energy that can be transported and stored. Electrical energy has become established as the form of energy here. Electrical energy can be obtained from renewable energy sources using electric machines which act as generators, transported by cables, temporarily stored in batteries and converted into motive energy by high-efficiency motors. The generators are in this case fixed in supporting structures which must withstand the natural forces of the renewable energy sources. It must be possible for the motors to be used efficiently, as well as effectively, in mobile applications. When using an electric machine as a generator or motor as high a power density as possible is desirable, because the power that can be supplied needs to be as high as possible in proportion to the mass of the electric motor, given that the smaller the mass of the generator, the more cheaply the mounting structure can be produced. In the case of the motor in the mobile application, for instance in a vehicle, the smaller mass moved means energy can be saved and thus the vehicle operated more cheaply.
In the past a reduction in the mass achieved for this purpose in the magnetically active part of the electric machine by optimizing the lamination geometry and selecting suitable materials for the metal sheets was often insufficient.
Thus on pages 68-70 of the magazine “antriebstechnik 5/2011” the authors Brand, Stahel and Vezzini describe a high-performance permanent magnet motor in which metal sheets made of cobalt-iron materials are used in the stator and rotor. The article primarily describes the need for a higher torque, which is achieved using metal sheets made of a cobalt-iron alloy with a saturation polarization of 2.35 Tesla compared to a silicon-iron material with a saturation polarization of 2.03 Tesla. It was possible to increase the maximum torque by 22% in this case. The last paragraph of the article states that instead of increasing the maximum torque, the volume and thus the weight of the motor can be reduced with the same maximum torque.
Although the article cited describes how cobalt-iron alloys have been the norm for decades in the aviation industry for reasons of weight reduction, nevertheless the weight reduction achieved by the use of cobalt-iron alloys is still not sufficient for many applications.